Comparison of the intraocular pressure-lowering effect and safety of brimonidine/timolol fixed combination and 0.5% timolol in normal-tension glaucoma patients

Abstract

Purpose: To compare the therapeutic efficacy and safety of brimonidine/timolol fixed-combination (BTFC) and 0.5% timolol ophthalmic solution in normal-tension glaucoma (NTG) patients.

Methods: This was a multi-institution, randomized, active-controlled, open-label, parallel-group study. After a full ophthalmic and glaucoma examination, a total of 110 NTG patients--55 undergoing therapy with BTFC and 55 0.5%, with timolol--participated in this study. Among them, 1 failed to meet the inclusion/exclusion criteria, 10 revoked their consent to participate in the study, 3 had adverse reactions, and 1 had a drug adherence rate of less than 70%. Ultimately, a total of 95 patients--48 in the BTFC group and 47 in the 0.5% timolol group--completed the study. The study visits took place at baseline and at 4 and 12 weeks. Diurnal IOP was measured at 9 a.m., 11 a.m., and 5 p.m. during the baseline visit and the visit at 12 weeks after eye-drop instillation. At each follow-up visit, compliance was assessed. Throughout the study, all adverse events were recorded and monitored by the investigators.

Results: The average difference in IOP change measured at 11 a.m. 12 weeks after administration between the two groups was 2.10 ± 2.59 mmHg. The BTFC group had a better IOP-lowering effect at all time points than did the 0.5% timolol group. The ratio of patients whose average IOP had decreased by >20% after 4 and 12 weeks was 50 and 56% in the BTFC group, respectively, whereas it was 29.41 and 23.53% in the 0.5% timolol group, respectively (p = 0.034, <0.001).

Conclusions: BTFC has a superior IOP-lowering effect than 0.5% timolol in NTG patients.

Keywords: 0.5 % timolol; Brimonidine/timolol fixed combination; Drug efficacy; Normal-tension glaucoma.